Catalytic treatment of hydrocarbons containing oxygenated compunds



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CA'rALYTIc TREATMENT or HYDRoCARBoNs coNrArNrNc oXYeENArEn coMr'oUNnsv Wiiliaml. Gilbert and WilliamA. Home, Okmonti, Pa.,

assignors to Gulfl Research vt Development Company, Pittsburgh, Pa.,` a-corporation of Delaware rIhis inventionV relates'to the catalytic treatmentI ofthe total liquid hydrocarbon product obtained hy the reaction of carbonmonoxide and a hydrogen-containing gas in the presence of a Fischer-Tropsch catalyst.

The catalytic hydrogenation of carbon monoxide in the presence of a Fischer-Tropsch catalyst at temperatures up to about 750 F. undersuperatmospheric pressures produces-a variety of substances, the predominance of a particularsubstance depending upon their particular operating conditions employed in carrying out the synthesis. In general, the materials whichare produced by the synthesis reaction comprise organic oxygenated compounds and hydrocarbons. The hydrocarbons thus produced comprise essentially straight chain olens and parafns. The-presentinvention is concerned with-the' conversion of oXygenated-compounds to hydrocarbonsandthe improvement of olens through isomerization.

The hydrocarbonswhich are separated from the reaction products obtained in the synthesis process invariably contain a small amount of organic oxygenated compounds.- The organicoxygenated compounds which may comprise alcohols, aldehydes, ketones andacids are undesirable in hydrocarbons boiling` in the motor fuel@ boiling range in that they greatly decrease the octane number of the motor fuel. Likewise, the oxygenated compounds hai/eva deleterious elfectlon thefcetane numberl of hydrocarbons-boilingl in the diesel fuelboiling range;w

Attempts have-been made to hydrogenate 'carbonmoir oxide to produce hydrocarbons devoid of oxygenated-compounds but invariably small` amounts of the latter are formed. Methods have been devised for separatinglthe oxygenated compounds from the hydrocarbonsbut these methods `for one-or more reasons have not been'entirely satisfactory.

The present invention is directed to a process whichnot only converts tomcre desirable compounds the objectionable oxygenatedcompoundswhich are associated with the hydrocarbons producedby the reaction ofcarbon monoxide and hydrogen in the presence ofva Fischer-Tropsch catalyst but also improves the octane rating` and the cetane ratin'gofthe hydocarbonsboiling linthe motor fuel and diesel fuel boilingaranges, respectively. The process of the invention has the further advantage in thatit makes more economic useof the catalyst. Y

The process of the present invention` comprise-s sepa rating the total liquidV hydrocarbon product containing olelins and oxygenatedcompounds obtained hy 'the reaction of carbon: monoxide and a hydrogencont"'ning gas into a fraction boiling in themotor fuel boiling ,76, a fraction boiling in the diesel fuel boiling range, and a residual fraction-comprisinga waxy` residue boiling above the diesel fuel'fraction. Themotor fuel fraction-is contacted under deoxoisomerizing conditions comprising a temperature of'about 500 toabout 11009 F. in the pres@ enceof a catalyst comprisingf alumina impregnatedwith anhydrous hydrogen chloride. The diesel fuel fraction:is contacted ataftemperaturefbetweenabout 5009 and d 10G F. under st ibstantially--A non-isomerizing`f conditiousiirlf the 2,816,906 listenin? Pes-J7, 19357 presence of catalyst withdrawn from thel deoxoisorheri'zing reaction zone'.-

By theterm' deoxoisomerizing" as used' herein and in the appended' claims'we are referring to the` simultaneous deo'xygenation of oxygenated compounds'- to olefins' andisomerizan'on of straight chain olenns to branched chain olens; The'process of deoxygenating 'while sim'ultaneously isomerizing'a synthetic motor fuel is'de'ned in U. S'. Patent No. 2,589;273 to Charles W. Montgomery a'nd William I; Gilbert'.

The'process'of the invention comprises a` cyclic catalyticfprocess whereina synthetic dieselfuel fraction is deoxygenated' in the presence of catalyst withdrawn'wfrom the deoxoisomerization of a synthetic motor fuel fraction and thefsynthetic motor fuel fraction"v is' deoxoisomerized in the presence of regenerated catalyst fromA said' deoxygenation-reaction.

The catalystwhich is Withdrawn frolirthe dedxoisomerizing zoeiispartially spent insofar as its promoting to any great'degree further son'ierizatio'n. We have found, however, that this catalyst is' a'n` effective'catalyst' for'promotingtdeoxyg'enation reactions.' Inorder that'the hydrocarbonsfboiling in` the diesel fuel range will not be iso'nierized, wefhave found it advantageous to employ a small amountI of ammonia in combinationwiththe diesel fuel fraction. While the ammonia'isfadvantageously'passedin combination with the diesel fuelfraction over the spent deoxoisomerizing catalyst, goodresults` canbe obtained by treating this catalyst with ammoniapri`orto` contacting thefhydrocarbons boiling'inthe-diesel fuel range-witli-'the catalyst;4

Deoxygenation in the presence of ammonia can be carried out' either at atmospheric or superatinospheric Nice pressure," i; e. pressures fromO to 200 poundsfper' square 'ratio of ammonia to liquid hydrocarbonscomprises-about 0.0005 to'0.0025 volume ofvliquidy ammoniaper volume ofI liquidfhydrocarbon charge. When th'e `catalystisinter mittently' treated-with ammonia, thamount oflammonia so employedY is'approximately equal to that which would beemployed if the ammonia*y wereY added continuously.' Treatingfof the catalyst-with ammonia is continueduntil the olefin isomerizing vactivity ofthe catalystE is sub1 stantially destroyed.

The catalystv which we employ 'for deoxoismerizin'g the motor fuel fraction comprisesaluminaimpregnated with anhydrous hydrogen chloride. As the catalyst' is used; ittgradu'ally' loses some of' its hydrogenf chloride contentvwith the result that' itsisomerizingactivityis' de; creased. This: catalyst,A however, is' `satisfactory for deoxygenation'fsofthat prior to itsbeing burned-offend reactivatedwith anhydrous hydrogen chloride,; the'fspent catalyst-is used for deoxygenation of the Diesel-fueljfrac tion; After the catalyst has been used for deoxygenation; itis then burned-off and reactivated forA furtherj'deoxoisomerizati'on. The catalyst'is preferably in powdered or finely divi-ded form with about 9,5` to `percentpassi`ng through a 100 mesh screen. The amount'of makc-upcatf alyst'isfrelatively small.1 However, when'necessary, nifakel'f `duit 13 to fractionator 14.

The present invention will be described more fully hereinbelow in conjunction with the accompanying ow diagram which illustrates diagrammatically a preferred .embodiment of the invention.

Now referring to the drawing, hydrocarbon charge containing olefins and oxygenated compounds obtained, for example, from the reaction of carbon monoxide and hydrogen in a Fischer-Tropsch process (not shown) is introduced by pump 10 through conduit 11 to heater 12. The hydrocarbon charge may comprise up to weight percent butanes and lighter, 50 to 80 weight percent boiling within the range, from room temperature to 400 F. comprising hydrocarbons boiling in the motor fuel boiling range, to 20 weight percent boiling within the range 400 to 650 F. comprising hydrocarbons boiling in the diesel fuel boiling range, and 10 to 25 weight percent waxy residue boiling above about 650 F.

Heated hydrocarbon charge is then passed through conln fractionator 14, the charge is separated into three fractions. A fraction comprising hydrocarbons and oxygenated compounds boiling in the motor fuel boiling range is removed overhead from fractionator 14 by conduit 16 through condenser 17 and conduit 18 to receiving vessel 19. Any light gases present are `removed from vessel 19 by conduit 21. A fraction com- -prising hydrocarbons and oxygenated compounds boiling in the diesel fuel boiling range is removed from fractionator 14 by conduit 22 and collected in a receiving vessel 23. A waxy residual fraction comprising hydrocarbons and oxygenated compounds boiling above about 650 F. is removed from the bottom of fractionator 14 through conduit 24.

The motor fuel fraction collected in vessel 19 is recycled in part as reux to fractionator 14 by conduits 26 4and 27 and pump 28. The remainder of the motor fuel fraction is passed through conduits 26 and 29 by pump 31 to heater 32. The motor fuel fraction is heated in lheater 32 to a temperature of about 500 to about 1100 F. and then passed through conduit 33 to catalyst transfer conduit 34. The catalyst in transfer conduit 34 comprises regenerated catalyst which is removed from regenator 48 by catalyst leg 35. Anhydrous hydrogen chloride is introduced into the motor fuel fraction by conduit 36. Instead of introducing the anhydrous hydrogen chloride with the motor fuel fraction, the anhydrous hydrogen chloride can, if desired, be passed by valved-conduit 30 into catalyst transfer conduit 34 prior to contacting the catalyst with the motor fuel fraction. The amount of anhydrous hydrogen chloride is suflcient to improve the isomerizing activity of the alumina and ordinarily comprises about 1 to 2O volumes of anhydrous hydrogen chloride per volume of catalyst. The motor fuel fraction and catalyst passes from conduit 34 into deoxoisomerizer 37. Deoxoisomerizer 37 is advantageously provided with a perforated plate 40 designed to retard the downward ow of catalyst. In deoxoisomerizer 37 the fraction boiling in the motor fuel boiling range is simultaneously deoxygenated and isomerized. Simultaneous deoxygenation and isomerization is advantageously carried out at about 500 to about 1100 F. in the presence of a tinely divided catalyst comprising alumina impregnated with anhydrous hydrogen chloride.

The anhydrous hydrogen chloride which is introduced with the motor fuel fraction maintains the isomerizing activity of the catalyst over a prolonged period of time. Chlorine, however, has a detrimental elect upon the lead susceptibility of the product. Therefore, the product should be treated to insure that no chlorine is present. Accordingly, the hydrocarbon product which is removed from the top of the deoxoisomerizer 37 through cyclone separator 38 is passed by conduit 39 to bauxite treater 41. The treating is advantageously carried out at about 400 fo about 950 -F. and space velocity of 0.1 to 30 volumes of gasoline per volume of bauxite per hour. The dtf chlorinated product is removed from bauxite treater 41 by conduit 42.

Catalyst which has lost a substantial part of its isomerizing activity is withdrawn from the bottom of deoxoisomerizer 37 by spent catalyst leg 46, advantageously of suiicient length that the dense body of catalyst therein forms an effective seal against the upward passage of gases from deoxygenator 49. A ow valve 44, advantageously of the slide valve type, controls the downward ow of catalyst. A portion of the catalyst withdrawn by catalyst leg 46 is passed by transfer conduit 47 to regenerator 48. The amount of catalyst sent to regenerator 48 through transfer conduit 47 is controlled by valve 45. The spent catalyst in transfer conduit 47 is picked up by a current of hot air and/ or flue gas introduced by conduit 71. The remainder of the catalyst withdrawn by catalyst leg 46 is passed to deoxygenator 49. Any make-up catalyst which is required is introduced into catalyst leg 46 by conduit 51.

The fraction comprising diesel fuel containing olefins and oxygenated compounds collected in receiving vessel 23 is passed by pump 52 through conduit 53 to heater 54. The diesel fuel fraction is heated to a temperature of about 500 to about 1100 F. in heater 54. The heated diesel fuel fraction is then passed through conduit 56 to conduit 57 wherein it is admixed with a small amount of ammonia which is introduced into conduit 57 by flow control valve 58. The amount of ammonia introduced is controlled by pH meter 59. When the pH of the aqueous product separated from the diesel fuel product falls below about 6.5, How valve 58 opens to allow more ammonia to be introduced with the diesel fuel fraction.

The combined diesel fuel and ammonia stream is introduced into deoxygenator 49 which is maintained at about 500 to about 1100 F. The ammonia need not be introduced with the diesel fuel fraction. If desired, the catalyst can be contacted with ammonia prior to introducing the diesel fuel fraction. In such case, the ammonia can be introduced into catalyst leg 46 by valvedconduit 60. Deoxygenator 49 is advantageously provided with a perforated plate 50 designed to retard the downward ow of catalyst and to promote uniform contact of the diesel fuel fraction and ammonia with the catalyst. Deoxygenated diesel fuel product and water are removed from the top of deoxygenator 49 through cyclone separator 61 and conduit 62. The product then is passed through condenser 63 and conduit 64 to diesel fuel receiving vessel 66. Any excess ammonia present or light gases formed during deoxygenation are vented from the top of vessel 66 through conduit 67. Water which is formed during deoxygenation is removed from vessel 66 by conduit 68 containing pH meter 59. Diesel fuel is removed from vessel 66 by conduit 69.

Spent catalyst from deoxygenator 49 is withdrawn through spent catalyst leg 72 which is advantageously of suflicient length that the dense body of catalyst therein forms an effective seal against the upward passage of conveying medium introduced by conduit 74. A conventional valve 73 suitably of the slide valve type for controlling the downward ow of catalyst is interposed in catalyst leg 72. From catalyst leg 72, the spent catalyst is picked up by a current of hot air and/ or flue gas from heater 75 and carried upwardly through riser pipe 76 to regenerator 48. Since the amount of diesel fuel hydrocarbons produced in a Fischer-Tropsch process may be about one-fifth the amount of gasoline boiling range hydrocarbons, the amount of catalyst passing to regenerator 48 in riser pipe 76 may be about one-fifth the amount of catalyst in transfer conduit 47. It will be understood, however, that this is not a set proportion and that the proportionate amount of catalyst in the various units will vary depending upon the make-up of the total hydrocarbon charge.

Regenerator 48 is advantageously provided with a perforated plate 81 designed to retard the downward flow stai stone with iiue gas and then regenerate with air and liue gas or'I Burning-off is carried out at a steam if necessary. temperature below the vsintering temperature of the catalyst, i. e., below about 1200 F. Afterthe catalyst has been burned oif, it` gravitates through the perforations in plate rS1 and forms a dense phase in catalyst leg35.` Cata- Y lyst leg ,35 has ai-ow valve 82'interposed in the lower extremity thereof-tocontrol the amount of catalyst which is put back intoV the system. The regenerated catalyst is then picked up bythe stream of vaporized orfpartially vaporized motor fuel fraction and anhydroushydrogen chloride and returned to the deoxoisomerizer 37. From the upper section of regenerator 48, the hot products of combustion pass-through cycloneseparator'lSS and out through conduit 84.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. In a process for simultaneously deoxygenating and isomerizing a motor fuel fraction comprising hydrocarbons boiling within the range of from room temperature to 400 F. and deoxygenating a diesel fuel fraction comprising hydrocarbons boiling within the range 400 F. to 650 F., each fraction having been obtained by the reaction of carbon monoxide and a hydrogen-containing gas, the improvement which comprises (l) deoxygenating the diesel fuel fraction in the presence of ammonia in an amount sufficient to substantially inhibit hydrocarbon isomerization with unregenerated catalyst selected from the group consisting of alumina, bauxite and fullers earth which has been directly withdrawn from simultaneously deoxygenating and isomerizing the motor fuel fraction and (2) simultaneously deoxygenating and isomerizing the motor fuel fraction with regenerated catalyst from the diesel fuel deoxygenating reaction.

2. In a process for simultaneously deoxygenating and isomerizing a motor fuel fraction comprising hydrocarbons boiling Within the range of from room temperature to 400 F. and deoxygenating a diesel fuel fraction comprising hydrocarbons boiling within the range of 400 to 650 F., each fraction having been obtained by the reaction of carbon monoxide and a hydrogen-containing gas, the improvement which comprises (1) contacting the diesel fuel fraction together with ammonia with unregenerated catalyst Selected from the group consisting of alumina, bauxite and fullers earth which has been directly withdrawn from simultaneously deoxygenating and isomerizing the motor fuel fraction and (2) contacting the motor fuel fraction together with anhydrous hydrogen chloride with regenerated catalyst from the diesel fuel deoxygenating reaction.

3. In a process for simultaneously deoxygenating yand isomerizing a motor fuel fraction comprising hydrocarbons boiling within the range of from room temperature to 400 F. in the presence of alumina impregnated with anhydrous hydrogen chloride and deoxygenating a diesel fuel fraction comprising hydrocarbons boiling within the range 400 to 650 F., each fraction having been obtained by the reaction of carbon monoxide and a hydrogen-containing gas, the improvement which comprises withdrawing catalyst consisting of finely divided alumina impregnated with anhydrous hydrogen chloride from the zone wherein the motor fuel fraction is simultaneously deoxygenated and isomerized, said catalyst being partially spent insofar as its promoting further isomerization; dividing said withdrawn catalyst into two portions; passing one of said portions into a regeneration zone and the remaining portion together with ammonia nter. ther diesel. truely:.deoxygenatingfzone;. withdrawing `spent catalyst frontsV the f diesel fuel. `:deoxygenating f. zone; .passingv saidsspent deoxygenatingzcatalyst to thefregen- `eration zone-,legeneratingzthe catalyst intheregeneration zone; zand, :passing the ,f regenerated. catalyst. to the..zone wherein :the motor. .ifuel fraction: is Jsimultaneously deoxygenated and: isomerized.;

4./.A.process for the.- catalytic v.treatment gofthe total liquidvhydrocarbon .product .containing olefnsand oxy- .genated compounds Aobtained :bythe =reactionof carbon monoxide and a .hydrogenfcontaining gas which-comprises separating .said liquidhydrocarbon product into a fraction boiling within the range of from room temperature to,:400f comprising hydrocarbons boilingin the vmotor fuel .boiling range, a fraction boiling. within the range 400 to 650 comprising hydrocarbons boiling in the dieselfuel boilingrange, and a residual fraction comprisinga waxyresiduevboiling Yabove the diesel'fuelfractiong'fsimultaneously deoxygenating `and 'isomerizing the motor fuel fraction at a temperature of about 500 to 1100 F. in the presence of finely divided alumina im pregnated with anhydrous hydrogen chloride; and deoxygenating the diesel fuel fraction in the presence of ammonia in an amount suicient to substantially inhibit hydrocarbon isomerization and to maintain the pH of the aqueous product released in the diesel fuel deoxygenation reaction above about 6.5 at a temperature of about 500 to about 1100 F. with unregenerated catalyst comprising catalyst which has been directly withdrawn from simultaneously deoxygenating and isomerizing the motor fuel fraction.

5. A process for the catalytic treatment of the total liquid hydrocarbon product containing olefins and oxygenated compounds obtained by the reaction of carbon monoxide and a hydrogen-containing gas which comprises separating said liquid hydrocarbon product into a fraction boiling within the range of from room temperature to 400 F. comprising hydrocarbons boiling in the motor fuel boiling range, a fraction boiling within the range 400 to 650 F. comprising hydrocarbons boiling in the diesel fuel boiling range, and a residual fraction comprising a waxy residue boiling above the diesel fuel fraction; contacting the motor fuel fraction together with anhydrous hydrogen chloride at a temperature of about 500 to about 1100 F. ina zone containing finely divided alumina; passing motor fuel thus obtained over bauxite at about 400 to about 950 F. and a space velocity of 0.1 to 30 volumes of motor fuel per volume of bauxite per hour; and contacting the diesel fuel fraction together with ammonia in an amount suiiicient to substantially inhibit hydrocarbon isomerization and to maintain the pH of the aqueous product released in the diesel fuel deoxygenation reaction above about 6.5 at a temperature of about 500 to about 1100 F. with unregenerated catalyst which has been directly withdrawn from the zone wherein the motor fuel fraction has been treated, said withdrawn catalyst being partially spent insofar as its promoting further isomerization.

6. A process for the catalytic treatment of the total liquid hydrocarbon product containing oleiins and oxy genated compounds obtained by the reaction of carbon monoxide and a hydrogen-containing gas which comprises separating said liquid hydrocarbon product into a fraction boiling Within the range of from room temperature to 400 F. comprising hydrocarbons boiiing in the motor fuel boiling range, a fraction boiling within the range 400 to 650 F. comprising hydrocarbons boiling in the diesel fuel boiling range, and a residual fraction comprising a waxy residue boiling above the diesel fuel fraction; contacting the motor fuel fraction together with anhydrous hydrogen chloride at a temperature of about 500 to about 1100 F. in a zone containing finely divided alumina, the ratio of anhydrous hydrogen chloride to alumina comprising about 1 to 20 volumes of anhydrous hydrogen chloride per volume of alumina; passing 7 the motor fuel thus obtained over bauxite at about 400 to about 950 F. and a space velocity of about 0.1 to 30 volumes of motor fuel per volume of bauxite per hour; and contacting the diesel fuel fraction together with ammonia in an amount sufcient to substantially inhibit hydrocarbon isomerization and to maintain the pH of the aqueous product released in the diesel fuel deoxygenation reaction above about 6.5 at a temperature of about 550 to about 750 F. with unregenerated catalyst which has been directly withdrawn from the zone wherein the motor fuel fraction has been treated, said withdrawn catalyst being partially spent insofar as its promoting further isomerization.

7. The process of claim 6 wherein the alumina comprises a mixture of regenerated spent catalyst from the zone wherein the motor fuel fraction has been treated and regenerated spent diesel fuel deoxygenating catalyst.

8. The process of claim 6 wherein the alumina comprises a mixture of spent catalyst from the zone wherein References Cited in the le of this patent UNITED STATES PATENTS 1,895,529 Taylor et al. Jan. 31, 1933 2,373,153 Tollefson Apr. 10, 1945 2,397,639 Berg et al Apr. 2, 1946 2,400,409 Hale et al May 14, 1946 2,470,216 Keith May 17, 1949 2,577,563 Belchetz Dec. 4, 1951 2,583,164 Watson Ian. 22, 1952 2,589,273 Montgomery et al Mar. 18, 1952 2,666,732 McConnell Ian. 19, 1954 2,666,733 Scovill Ian. 19, 1954 2,700,676 McGrath Jan. 25, 1955 

1. IN A PROCESS FOR SIMULTANEOUSLY DEOXYGENATING AND ISOMERIZING A MOTOR FUEL FRACTION COMPRISING HYDROCARBONS BOILING WITHIN THE RANGE OF FROM ROOM TEMPERATURE TO 400*F. AND DEOXYGENATING A DIESEL FUEL FRACTION OCMPRISING HYDROCARBONS BOILING WITHIN THE RANGE 400*F. TO 650*F. EACH FRACTION HAVING BEEN OBTAINED BY THE REACTION OF CARBON MONOXIDE AND A HYDROGEN-CONTAINING GAS THE IMPROVEMENT WHICH COMPRISES (1) DEOXYGENATING THE DIESEL FUEL FRACTION IN THE PRESENCE OF AMMONIA IN AN AMOUNT SUFFICIENT TO SUBSTANTIALLLY INHIBIT HYDROCARBON ISOMERIZATION WITH UNREGENERATED CATALYST SELECTED FROM THE GROUP CONSISTING OF ALUMINA, BAUXITE AND FULLER''S EARTH WHICH HAS BEEN DIRECTLY WITHDRAWN FROM SIMULTANEOUSLY DEOXYGENATING AND ISOMERIZING THE MOTOR FUEL FRACTION AND (2) SIMULTANEOUSLY DEOXYGENATING AND ISOMERIZING THE MOTOR FUEL FRACTION WITH REGENERATED CATALYST FROM THE DIESEL FUEL DEOXYGENATING REACTION. 